Seafloor Stadium
Land-Plains Island (Rare)

(Tap: Add W or U to your mana pool.)

Seafloor Stadium enters the battlefield tapped unless you reveal a Bird card from your hand.

U, Tap, Sacrifice Seafloor Stadium: Return target creature you control to its owner's hand.

2, Tap: Target land becomes a 3/3 white Knight creature until end of turn. It's still a land.

Lars Moeller